Disposable absorbent articles, such as sanitary napkins, are well known in the art, and typically include a fluid pervious body facing cover layer, a liquid impermeable garment facing layer, and an absorbent core structure arranged between the cover layer and garment facing layer. Optionally, such articles may further include a transfer layer arranged between cover layer and the core.
Absorbent core structures used in disposable absorbent articles are typically made mainly of hydrophilic fibrous material such as cellulosic fibers. Such absorbent core structures may also include hydrogelling absorbent materials intermixed with such fibrous material to thereby increase the absorbent capacity of the core structure. Such hydrogelling absorbent materials are polymers that can absorb large quantities of liquid and thus are commonly known as “superabsorbent polymers” or “SAP”.
The inventors of the present invention have discovered that conventional multi-layer core structures having a high superabsorbent polymer content typically have relatively poor structural integrity properties due to the fact that the superabsorbent polymer tends to prevent the effective bonding of the constituent core layers. This problem is further exacerbated when the absorbent core absorbs fluid because the superabsorbent polymer swells upon absorption of fluid thereby further reducing the structural integrity of the core structure. The relatively poor structural integrity of conventional core structures containing high levels of superabsorbent may cause absorbent articles containing such cores to structurally fail during manufacture or use.
Surprisingly, the absorbent core structures according to the present invention have a high degree of structural integrity despite containing high levels of superabsorbent polymer. Absorbent articles according to the present invention, including such inventive core structures, are extremely thin, highly absorbent and also retain a high level of structural integrity before and during use.